(a) Field of the Invention
The present invention relates to a method and an apparatus for discovering a target in device-to-device direct communication, and more particularly, to a method and an apparatus capable of rapidly selecting a target device having a desire to communicate among a large number of surrounding devices.
(b) Description of the Related Art
The majority of mobile services which are currently used have Internet-based communication structure via a base station such as 3G, LTE, and LTE-A or separate access point (AP) equipment such as WiFi AP. In the environment of the majority of mobile services, even in the case in which a simple message is intended to be transmitted to another user in close proximity to a user, since the base station or the AP equipment should be used, a service delay and charging may occur.
Meanwhile, device-to-device direct communication enables direct communication between two devices that are adjacent to each other without using the base station or the AP equipment, and uses communication techniques such as Bluetooth, Wi-Fi, direct near field communications (NFC), and the like. Device-to-device direct communication using NFC and WiFi P2P is broadly used in home appliances and office machines that are recently released as well as mobile devices, and as a result, provides convenient functions capable of controlling the home appliances or the office machines by the mobile devices.
In order to perform the above-mentioned device-to-device direct communication, it is required to discover a desired target device. However, in a wireless communication environment in which a large number of devices are scattered, communication within a close distance has disadvantages that it spends much time in discovering the target device and it may also access only in the case in which it has advance information on the target device. Further, in the future, since it is expected that the device-to-device direct communication will be further activated, the more devices there are, the more difficult the discovery of an accurate target is.
Meanwhile, as a technique for rapidly discovering the target device, a look and link communications method has been used. That is, examples of the look and link communications method for rapidly discovering the target device include a method using an image, a method using a radio wave, and a method using a sound wave. The method using an image is a method of photographing the target device using a camera of a mobile device and determining whether or not the photographed target is the same as a desired target device. The method using a radio wave is a method in which a sharp radio wave beam is transmitted to the target device and the target device receiving the sharp radio wave beam recognizes reception of a connection request from someone and responds to the connection request. The method using a sound wave is a method in which the sound wave instead of the radio wave is used and the target device receiving the sound wave responds. The above-mentioned methods may be solely used and may be used in combination according to the purpose.
Once the look and link communications method is used, the target device may be discovered even in the case in which ID such as an address or number of the target device is not known, and the target device may be discovered within three seconds as compared to a case in which an existing Bluetooth or Wi-Fi Direct takes thirty seconds or more, thereby making it possible to dramatically reduce a time taken to search and discover the device.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.